qemu-patch-raspberry4/linux-user/arm/target_structs.h
Laurent Vivier 7f254c5cb8 linux-user: remove useless padding in flock64 structure
Since commit 8efb2ed5ec ("linux-user: Correct signedness of
target_flock l_start and l_len fields"), flock64 structure uses
abi_llong for l_start and l_len in place of "unsigned long long"
this should force them to be aligned accordingly to the target
rules. So we can remove the padding field and the QEMU_PACKED
attribute.

I have compared the result of the following program before and
after the change:

    cat -> flock64_dump  <<EOF
    p/d sizeof(struct target_flock64)
    p/d &((struct target_flock64 *)0)->l_type
    p/d &((struct target_flock64 *)0)->l_whence
    p/d &((struct target_flock64 *)0)->l_start
    p/d &((struct target_flock64 *)0)->l_len
    p/d &((struct target_flock64 *)0)->l_pid
    quit
    EOF

    for file in build/all/*-linux-user/qemu-* ; do
    echo $file
    gdb -batch -nx -x flock64_dump $file 2> /dev/null
    done

The sizeof() changes because we remove the QEMU_PACKED.
The new size is 32 (except for i386 and m68k) and this is
the real size of "struct flock64" on the target architecture.

The following architectures differ:
aarch64_be, aarch64, alpha, armeb, arm, cris, hppa, nios2, or1k,
riscv32, riscv64, s390x.

For a subset of these architectures, I have checked with the following
program the new structure is the correct one:

  #include <stdio.h>
  #define __USE_LARGEFILE64
  #include <fcntl.h>

  int main(void)
  {
	  printf("struct flock64 %d\n", sizeof(struct flock64));
	  printf("l_type %d\n", &((struct flock64 *)0)->l_type);
	  printf("l_whence %d\n", &((struct flock64 *)0)->l_whence);
	  printf("l_start %d\n", &((struct flock64 *)0)->l_start);
	  printf("l_len %d\n", &((struct flock64 *)0)->l_len);
	  printf("l_pid %d\n", &((struct flock64 *)0)->l_pid);
  }

[I have checked aarch64, alpha, hppa, s390x]

For ARM, the target_flock64 becomes the EABI definition, so we need to
define the OABI one in place of the EABI one and use it when it is
needed.

I have also fixed the alignment value for sh4 (to align llong on 4 bytes)
(see c2e3dee6e0 "linux-user: Define target alignment size")
[We should check alignment properties for cris, nios2 and or1k]

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20180502215730.28162-1-laurent@vivier.eu>
2018-05-03 18:40:19 +02:00

60 lines
2.2 KiB
C

/*
* ARM specific structures for linux-user
*
* Copyright (c) 2013 Fabrice Bellard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef ARM_TARGET_STRUCTS_H
#define ARM_TARGET_STRUCTS_H
struct target_ipc_perm {
abi_int __key; /* Key. */
abi_uint uid; /* Owner's user ID. */
abi_uint gid; /* Owner's group ID. */
abi_uint cuid; /* Creator's user ID. */
abi_uint cgid; /* Creator's group ID. */
abi_ushort mode; /* Read/write permission. */
abi_ushort __pad1;
abi_ushort __seq; /* Sequence number. */
abi_ushort __pad2;
abi_ulong __unused1;
abi_ulong __unused2;
};
struct target_shmid_ds {
struct target_ipc_perm shm_perm; /* operation permission struct */
abi_long shm_segsz; /* size of segment in bytes */
abi_ulong shm_atime; /* time of last shmat() */
abi_ulong __unused1;
abi_ulong shm_dtime; /* time of last shmdt() */
abi_ulong __unused2;
abi_ulong shm_ctime; /* time of last change by shmctl() */
abi_ulong __unused3;
abi_int shm_cpid; /* pid of creator */
abi_int shm_lpid; /* pid of last shmop */
abi_ulong shm_nattch; /* number of current attaches */
abi_ulong __unused4;
abi_ulong __unused5;
};
struct target_oabi_flock64 {
abi_short l_type;
abi_short l_whence;
abi_llong l_start;
abi_llong l_len;
abi_int l_pid;
} QEMU_PACKED;
#endif